print validation errors when gitlab-rake gitlab:import:repos fails for project

Currently, when gitlab-rake gitlab:import:repos is not able to import a project it justs prints "Failed trying to create project" to the console. There seems to be no way to find out what exactly has failed. Since the check uses validation, it should at least print the validation issues. That might be a bit cryptic, but may be better than leaving the user in the dark completely.